The Anisotropy of Myelin Magnetic Susceptibility

Peter van Gelderen¹, Hendrik Mandelkow¹, Jacco A. De Zwart¹, Jeff H. Duyn¹

MR measurements and model calculations suggest that the magnetic susceptibility of myelin is anisotropic, and this property strongly affects T2* relaxation and its orientation dependence in white matter of human brain. Direct measurement of this anisotropic susceptibility by MRI is in principle possible, but practically difficult and potentially confounded by effects from microscopic tissue compartmentalization. Therefore, we present an independent measurement of anisotropic susceptibility based on the torque experienced by white matter in a spinal cord sample suspended in a homogeneous 7T field.